It's possible that they could do Catwoman without the actual feline costume. She could simply be a skilled cat burglar, who wears a mask tight-fitting catsuit (as oppose to a Cat suit). Something like Catherine Zeta Jones in Entrapment. Or perhaps after the tabloids refer to the mystery 'Catwoman' thief, she starts wearing cat ears along with her mask and donning claws, to play up to the nickname. Just a possible way of distinguishing her from Michelle Pfeiffer's memorable take.